Forensic Medicine
1 questionsIn medical negligence cases, what is the primary role of the plaintiff?
NEET-PG 2012 - Forensic Medicine NEET-PG Practice Questions and MCQs
Question 711: In medical negligence cases, what is the primary role of the plaintiff?
- A. Files case in civil court (Correct Answer)
- B. Acts as defender
- C. Gives judgement
- D. Issues summons to defendant
Explanation: ***Files case in civil court*** - The **plaintiff** is the party who initiates a lawsuit, claiming to have been harmed by the actions of another party. - In medical negligence cases, this typically involves someone who alleges injury due to substandard medical care and seeks **compensation** through the legal system. - Filing the case in civil court is the **primary and defining role** of the plaintiff. *Acts as defender* - The **defender** (or defendant) is the party against whom a lawsuit is brought, and they are responsible for responding to the plaintiff's claims. - In medical negligence, the healthcare provider accused of negligence would be the defender. *Gives judgement* - Giving judgment is the function of the **court** or judge and is a neutral adjudication of the facts and application of the law. - The plaintiff's role is to present their case and evidence to persuade the court, not to issue the final decision. *Issues summons to defendant* - Issuing summons is a **court function**, not the plaintiff's role. - The court issues summons after the plaintiff files the case, directing the defendant to appear and respond to the allegations.
Internal Medicine
1 questionsWhich visual disturbance is commonly associated with Vitamin B12 deficiency?
NEET-PG 2012 - Internal Medicine NEET-PG Practice Questions and MCQs
Question 711: Which visual disturbance is commonly associated with Vitamin B12 deficiency?
- A. Centrocaecal scotoma (Correct Answer)
- B. Binasal hemianopia
- C. Constriction of peripheral vision
- D. Bitemporal hemianopia
Explanation: No relevant citations could be added to the original explanation because the provided references did not specifically address the association between Vitamin B12 deficiency and centrocaecal scotoma. ***Centrocaecal scotoma*** - **Vitamin B12 deficiency** can lead to optic neuropathy, which often manifests as a **centrocaecal scotoma**, affecting central and paracentral vision. - This visual impairment is due to **demyelination of the optic nerve fibers** caused by the deficiency. *Binasal hemianopia* - This type of visual field defect is rare and typically caused by lesions that compress the uncrossed retinal nerve fibers, such as **bilateral internal carotid artery aneurysms** or **bilateral optic nerve disease**. - It does not directly correlate with **Vitamin B12 deficiency**. *Constriction of peripheral vision* - **Peripheral vision loss** is associated with conditions like **glaucoma** or advanced **retinitis pigmentosa**. - It is not a characteristic visual disturbance of **Vitamin B12 deficiency**. *Bitemporal hemianopia* - This visual field defect is commonly caused by compression of the **optic chiasm**, most often due to a **pituitary adenoma**. - It results in loss of vision in the outer half of both visual fields and is not linked to **Vitamin B12 deficiency**.
Ophthalmology
4 questionsWhich type of cataract is specifically associated with decreased reading ability?
What is the primary mechanism of pathogenesis in acute angle closure glaucoma?
What condition is characterized by cherry red spot at the macula with retinal whitening?
Most common cause of bilateral optic atrophy is:
NEET-PG 2012 - Ophthalmology NEET-PG Practice Questions and MCQs
Question 711: Which type of cataract is specifically associated with decreased reading ability?
- A. Blue dot cataract
- B. Nuclear cataract (Correct Answer)
- C. Fusiform cataract
- D. Punctate cataract
Explanation: ***Nuclear cataract*** - **Nuclear cataracts** cause progressive hardening and yellowing of the lens nucleus with increased refractive index - This produces a **myopic shift** that initially causes **"second sight"** (temporary improvement in near vision) - However, as the cataract progresses, the increasing opacity leads to **overall visual decline affecting both distance and near vision**, including reading ability - Among the given options, nuclear cataract is the most common age-related cataract that significantly impairs vision including reading *Blue dot cataract* - **Blue dot cataracts** (cerulean cataracts) are small, bluish peripheral opacities, usually congenital and stationary - They rarely cause significant visual impairment and do not affect reading ability *Fusiform cataract* - **Fusiform cataracts** are congenital spindle-shaped opacities along the visual axis - While they can affect vision if dense, they are rare and not typically associated with progressive reading difficulty *Punctate cataract* - **Punctate cataracts** are small, scattered dot-like opacities in the lens - They are often congenital or age-related and cause minimal visual disturbance - Not specifically associated with decreased reading ability
Question 712: What is the primary mechanism of pathogenesis in acute angle closure glaucoma?
- A. Increased secretion of aqueous humor
- B. Outflow obstruction due to anatomical factors (Correct Answer)
- C. Increased absorption of aqueous humor
- D. Decreased ciliary body function
Explanation: ***Outflow obstruction due to anatomical factors*** - **Acute angle-closure glaucoma (AACG)** occurs due to a sudden blockage of the **trabecular meshwork**, which is the primary drainage pathway for aqueous humor. - This blockage is caused by anatomical predispositions, such as a **narrow anterior chamber angle**, relatively large lens, and **pupillary block** leading to iris bombé with peripheral iris bowing forward. - The iridocorneal angle closure prevents aqueous humor drainage, causing **rapid IOP elevation**. *Increased secretion of aqueous humor* - While increased aqueous humor production can contribute to elevated intraocular pressure, it is **not the primary mechanism** in acute angle-closure glaucoma. - This mechanism is more relevant in **open-angle glaucoma** or conditions with ciliary body overactivity. - AACG's hallmark is **outflow obstruction**, not increased production. *Decreased ciliary body function* - Decreased ciliary body function would **reduce aqueous humor production**, leading to **hypotony** (low IOP), not elevated pressure. - This is the opposite of what occurs in AACG, where IOP rises dramatically due to impaired drainage. - Ciliary body dysfunction is seen in conditions like **uveitis** or post-surgical complications. *Increased absorption of aqueous humor* - **Increased absorption** of aqueous humor would **reduce intraocular pressure**, which is the opposite of what occurs in acute angle-closure glaucoma. - The disease is characterized by a **rapid and severe rise in intraocular pressure** due to impaired outflow, not enhanced absorption. - Normal aqueous absorption occurs via trabecular and uveoscleral pathways, both of which are blocked in AACG.
Question 713: What condition is characterized by cherry red spot at the macula with retinal whitening?
- A. CRVO
- B. CRAO (Correct Answer)
- C. Diabetic retinopathy
- D. Syphilitic retinopathy
Explanation: ***CRAO*** - **Central retinal artery occlusion (CRAO)** is characterized by **sudden, profound, painless monocular vision loss**. - The classic funduscopic finding is a **cherry-red spot at the macula** with diffuse **retinal whitening** due to ischemia. *CRVO* - **Central retinal vein occlusion (CRVO)** presents with **painless vision loss** but typically shows **hemorrhages**, **dilated tortuous veins**, and **cotton wool spots** on funduscopic exam. - It does not usually cause retinal whitening or a cherry-red spot. *Diabetic retinopathy* - **Diabetic retinopathy** is characterized by **microaneurysms**, **hemorrhages**, **hard exudates**, and **cotton wool spots**, and can lead to neovascularization. - It does not present with acute retinal whitening or a cherry-red spot in the macula. *Syphilitic retinopathy* - **Syphilitic retinopathy** can cause a variety of presentations, including **retinal vasculitis**, **chorioretinitis**, and **optic neuritis**. - It does not typically manifest as a cherry-red spot with diffuse retinal whitening at the macula.
Question 714: Most common cause of bilateral optic atrophy is:
- A. Intracranial tumor
- B. Nutritional deficiency (B12/folate) (Correct Answer)
- C. Hereditary optic neuropathy
- D. Toxic optic neuropathy
Explanation: ***Nutritional deficiency (B12/folate)*** - **Nutritional optic neuropathy** due to deficiencies in B vitamins (especially B12, thiamine) and folate is a common cause of bilateral optic atrophy, particularly in **developing countries** and in populations with **malnutrition or chronic alcoholism**. - These deficiencies impair the **metabolism of retinal ganglion cells** and their axons, leading to symmetric bilateral optic nerve degeneration. - The condition is often **reversible in early stages** with appropriate supplementation. - **Note:** The "most common" cause varies by geographic location, population, and clinical setting. *Hereditary optic neuropathy* - **Leber's hereditary optic neuropathy (LHON)** and **autosomal dominant optic atrophy (ADOA)** are major causes of bilateral optic atrophy, especially in **younger patients**. - LHON typically presents in young males (15-35 years) with **sequential bilateral visual loss**. - These are among the **most common inherited optic neuropathies** and should always be considered in bilateral cases. *Intracranial tumor* - Intracranial tumors typically cause **unilateral optic atrophy** due to direct compression of one optic nerve. - **Bilateral optic atrophy** can occur with **chiasmal or suprasellar tumors** (pituitary adenomas, craniopharyngiomas) but is less common. - Usually presents with **visual field defects** (bitemporal hemianopia) before significant atrophy develops. *Toxic optic neuropathy* - **Toxic optic neuropathies** result from exposure to substances such as **methanol, ethambutol, tobacco-alcohol amblyopia**, or isoniazid. - Can cause bilateral symmetric optic atrophy but are **exposure-dependent** and less prevalent in general population. - **Tobacco-alcohol amblyopia** may overlap with nutritional deficiency.
Pharmacology
4 questionsLow molecular weight heparin mainly inhibits which factor?
What is the recommended dose of oseltamivir for a child aged 9 months?
Which of the following statements about vinca alkaloids is true?
Which of the following antineoplastic drugs SHOULD NOT be given by rapid IV infusion?
NEET-PG 2012 - Pharmacology NEET-PG Practice Questions and MCQs
Question 711: Low molecular weight heparin mainly inhibits which factor?
- A. Factor VIIIa
- B. Factor Xa (Correct Answer)
- C. Factor XIIa
- D. Factor IIa
Explanation: ***Factor Xa*** - Low molecular weight heparin (LMWH) primarily exerts its anticoagulant effect by binding to **antithrombin III** and increasing its inhibitory activity against **Factor Xa**. - This selective inhibition of Factor Xa, rather than Factor IIa (thrombin), accounts for its more predictable anticoagulant response and lower risk of bleeding compared to unfractionated heparin. *Factor VIIIa* - **Factor VIIIa** is a cofactor in the intrinsic pathway, crucial for activating Factor X, but it is not directly inhibited by LMWH. - Its inhibition is more characteristic of **activated protein C**, not LMWH. *Factor XIIa* - **Factor XIIa** is involved in the initiation of the intrinsic coagulation pathway and the kallikrein-kinin system. - LMWH has no significant inhibitory effect on Factor XIIa. *Factor IIa* - While unfractionated heparin inhibits **Factor IIa (thrombin)** relatively equally to Factor Xa, LMWH has a much weaker inhibitory effect on Factor IIa due to its shorter chain length. - The anti-Factor IIa activity of LMWH is generally considered to be negligible compared to its **anti-Factor Xa activity**.
Question 712: What is the recommended dose of oseltamivir for a child aged 9 months?
- A. 2 mg/kg twice daily for 5 days
- B. 2.5 mg/kg twice daily for 5 days
- C. 3 mg/kg twice daily for 5 days (Correct Answer)
- D. 3.5 mg/kg twice daily for 5 days
Explanation: ***3 mg/kg twice daily for 5 days*** - For children aged **less than 1 year**, and weighing less than 15 kg, the recommended oseltamivir dose is **3 mg/kg** administered **twice daily** for 5 days. - This dosage regimen is effective in treating influenza and is based on studies of its **pharmacokinetics** and **efficacy** in this age group. *2 mg/kg twice daily for 5 days* - This dosage is **lower than recommended** for children under 1 year of age and may not achieve adequate therapeutic drug levels. - Subtherapeutic dosing could lead to **reduced antiviral efficacy** and potentially poorer clinical outcomes. *2.5 mg/kg twice daily for 5 days* - Similar to the 2 mg/kg dose, this is **below the standard recommendation** for infants and young children in this age bracket. - Inadequate dosing increases the risk of **treatment failure** and the development of **antiviral resistance**. *3.5 mg/kg twice daily for 5 days* - This dosage might be considered **higher than necessary** for a 9-month-old child and could potentially increase the risk of **adverse effects**. - While exact toxicities are rare within a reasonable range, adherence to recommended guidelines optimizes the **benefit-risk profile**.
Question 713: Which of the following statements about vinca alkaloids is true?
- A. Inhibits mitotic spindle (Correct Answer)
- B. Enhances polymerization of tubulin
- C. Inhibits topoisomerase I
- D. Inhibits topoisomerase II
Explanation: ***Inhibits mitotic spindle*** - **Vinca alkaloids** (e.g., vincristine, vinblastine) exert their cytotoxic effects by binding to **tubulin**, thereby inhibiting its polymerization into microtubules. - This disruption prevents the formation of the **mitotic spindle**, arresting cells in metaphase and leading to apoptosis. *Enhances polymerization of tubulin* - This statement describes the mechanism of action of **taxanes** (e.g., paclitaxel), which stabilize microtubules and prevent their depolymerization. - Vinca alkaloids, in contrast, **inhibit** tubulin polymerization, preventing microtubule assembly. *Inhibits topoisomerase I* - Inhibition of **topoisomerase I** is the mechanism of action for drugs like **irinotecan** and **topotecan**. - These agents cause single-strand breaks in DNA, which is distinct from the microtubule disruption caused by vinca alkaloids. *Inhibits topoisomerase II* - Drugs like **etoposide** and **teniposide** work by inhibiting **topoisomerase II**, leading to double-strand DNA breaks. - This mechanism is different from the disruption of microtubule dynamics seen with vinca alkaloids.
Question 714: Which of the following antineoplastic drugs SHOULD NOT be given by rapid IV infusion?
- A. Cyclophosphamide
- B. Cytosine arabinoside
- C. Cisplatin (Correct Answer)
- D. Bleomycin
Explanation: ***Cisplatin*** - **Cisplatin** is highly nephrotoxic and emetogenic; rapid IV infusion can exacerbate these adverse effects, leading to severe renal damage and intractable nausea/vomiting. - It typically requires **prolonged infusion times** (e.g., 6-8 hours) with extensive pre- and post-hydration to reduce kidney toxicity and ensure patient tolerance. *Cyclophosphamide* - While cyclophosphamide can cause **hemorrhagic cystitis**, this is managed by adequate hydration and mesna, and its infusion rate is generally not as critically prolonged as cisplatin's. - It is often administered as a **relatively quick IV infusion** over 30-60 minutes, emphasizing hydration. *Bleomycin* - **Bleomycin** is known for pulmonary toxicity and hypersensitivity reactions, but these are not primarily linked to its infusion rate. - It is commonly given via **slow IV push or short infusion**, sometimes with a test dose to assess for hypersensitivity. *Cytosine arabinoside* - **Cytosine arabinoside** can cause myelosuppression and cerebellar toxicity, but these toxicities are not typically exacerbated by a rapid infusion rate. - It is often administered via a **continuous infusion** over several days or as a rapid IV bolus.